In a computer controlled system, information is presented to an operator on a display so that the operator can monitor the system. Typically, different types of information are displayed to the operator at different times depending, for example, on conditions of the system at a given time.
To program the system to display a particular type of information under specified conditions, a programmer has to scan through the operating program of the system to determine at which locations in the operating program the system will be in the specified conditions. The programmer then has to insert program code into the operating program at the determined locations to instruct the system to display the particular type of information. This process can be cumbersome for the programmer, which increases programming time, and is prone to programming error.